Method for manufacturing packaging structure

ABSTRACT

This invention relates to a packaging structure and method for manufacturing the packaging structure. The packaging structure comprises a substrate film, a plurality of chips, a compound resin layer and a support layer. The substrate film is formed with circuits having a plurality of terminals exposed from a solder mask. The chips, each of which has a plurality of pads, under bump metals (UBMs) formed on the pads, and composite bumps disposed onto the UBMs, are bonded onto the substrate film to form the first tape. The second tape comprises the support layer and the compound resin layer formed on the support layer. The first tape and the second tape are both in reel-form and are expanded towards a pair of rollers to be heated and pressurized for encapsulating the chips.

CROSS-REFERENCES TO RELATED APPLICATIONS

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a packaging structure and a method formanufacturing the packaging structure. More particularly, the presentinvention relates to a packaging structure using composite bumps and amethod for manufacturing the packaging structure in a manner ofreel-to-reel for mass production.

2. Descriptions of the Related Art

In modern advanced semiconductor manufacturing processes, semiconductordevices have been minimized to the nano-scale in mass production.Nano-scale packaging technologies applicable to such semiconductordevices have also emerged to accommodate the need of different products.Once the fabrication of an IC is completed on a wafer, the wafer has tobe transferred to a packaging facility for subsequent dicing andpackaging. The efficiency of the packaging process impacts theproduction cost and operational performance of the packaged chip.Accordingly, the packaging structure and material thereof have becomemore important.

Conventionally, a chip is electrically combined to a substrate, whenbumps of the chip electrically connect to the terminals of the substraterespectively. Because gold has the advantage of electrical conduction,the conventional bumps are made of gold. Furthermore, in theconventional process, after the chip is disposed onto the substrate,compound resin is further applied to encapsulate the chip.

Conceivably, due to gold being expensive and the process of respectivelyapplying the compound resin on to the chips being complex, the cost ofmanufacturing the packaging structure is high. Therefore, a novelpackaging structure and method for manufacturing the packaging structureneeds to be developed in this field.

SUMMARY OF THE INVENTION

The primary objective of this invention is to provide a packagingstructure and a method for manufacturing the packaging structure. Thepackaging structure comprises composite bumps which are made of Au/Cu orAu/Ni/Cu, in which Au forms a thickness which is less than a half of thetotal height of the composite bump. The reduction of Au results inreducing the manufacture cost.

Another objective of this invention is to provide a packaging structureand a method for manufacturing the packaging structure. The chips aredisposed onto the substrate film to form the first tape in a reel-form;the compound resin is applied onto a support layer in a widespreadmanner to form the second tape in a reel-form similarly. Subsequently,the first tape and the second tape can be spread towards a pair ofrollers to be heated and pressurized with each other. In this manner,the processes for manufacturing the packaging structure can besimplified.

To achieve the aforesaid objectives, the packaging structure of thepresent invention comprising a substrate film, a plurality of chips, acompound resin layer and a support layer. The substrate film is formedwith circuits having a plurality of terminals exposed from a soldermask. The chips are bonded onto the substrate film. Each of the chipshas a plurality of pads, under bump metals (UBMs) formed on the pads,and composite bumps disposed onto the UBMs, in which the composite bumpsis made Au/Cu or Au/Ni/Cu and electrically connects to the terminalsrespectively. The compound resin layer is formed on the substrate filmto encapsulate the plurality of chips.

Another preferable packaging structure of the present inventioncomprises a substrate film, a cover layer and a plurality of chips. Thesubstrate film is formed with circuits having a plurality of terminalsexposed from a solder mask. The cover layer is formed onto the terminal,wherein the cover layer is made of Ni/Au or Sn. The chips are bondedonto the substrate film. Each of the chips has a plurality of pads,under bump metals (UBMs) formed on the pads, and composite bumpsdisposed onto the UBMs. The composite bumps are made Au/Cu or Au/Ni/Cuand electrically connect to the terminals respectively. The UBMs extendand are partially exposed to form a test pad

Yet a further objective of this invention is to provide a method formanufacturing a packaging structure. The method comprises the steps of:providing a substrate film being formed with circuits having a pluralityof terminals exposed from a solder mask; providing a plurality of chips,each of the chips having a plurality of pads and a plurality ofcomposite bumps disposed onto the pads; bonding the plurality of chipsonto the substrate film to form a first tape, wherein the plurality ofcomposite bumps electrically connect to the terminals respectively;providing a support layer having a compound resin layer being appliedthereon to form a second tape; forming each of the first tape and thesecond tape into a reel; expanding and transporting the first tape andthe second tape towards a pair of rollers; pre-heating the second tapeto soften the compound resin layer thereof; and heating and pressurizingthe first tape and the second tape with each other to a temperature from100 to 250 degrees centigrade by a pair of rollers to implant the chipswithin the compound resin layer.

The detailed technology and preferred embodiments implemented for thesubject invention are described in the following paragraphs accompanyingthe appended drawings for people skilled in this field to wellappreciate the features of the claimed invention.

BRIEF DESCRIPTION OF THE DRAWINGS,

FIG. 1A is a schematic view illustrating the system for manufacturingthe packaging structure of the present invention;

FIG. 1B is a schematic view illustrating a unit by cutting the packagingstructure;

FIG. 1C is a schematic view illustrating the unit mounted with solderballs;

FIGS. 2A to 2C are schematic views illustrating various embodiments ofthe composite bumps;

FIG. 3 is a schematic view illustrating the step of applying the NCPonto the substrate film;

FIG. 4 is a schematic view illustrating the step of applying ultrasonicwaves to the chips;

FIG. 5A is a schematic view illustrating the first tape;

FIG. 5B is a schematic view illustrating the second tape; and

FIGS. 6A and 6B are flow charts illustrating the method of manufacturingthe packing structure of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1A and FIG. 1B, FIG. 1A shows the system formanufacturing the packaging structures 1, and FIG. 1B depicts a unit 1′formed by cutting the packaging structure 1. In the followingparagraphs, the packaging structure 1 will be disclosed in detail inadvance, and then the processes for manufacturing the packagingstructure 1 will be explained afterwards.

As shown in FIGS. 1A and 1B, the packaging structure 1 comprises asubstrate film 11, a solder mask 15 formed on the substrate film 11, aplurality of chips 12 being bonded onto the substrate film 11, acompound resin layer 13 being formed on the substrate film 11 toencapsulate the chips 12, and a support layer 14 overlaying the compoundresin layer 13.

The substrate film 11 includes circuits (not shown in the figures) and asolder mask 1, in which the circuits have a plurality of terminals 111exposed from a solder mask 15. The substrate film 11 and the supportlayer 14 can be made of polyimide (PI) or polyethylene terephthalate(PET). Also referring to FIGS. 2A and 2B, the chip 12 comprises aplurality of pads 121, a plurality of under bump metals (UBMs) 122 and aplurality of composite bump 123. The UBMs 122 are formed on the pads 121and the composite bumps 123 are then disposed onto the UBMs 122respectively. Preferably, each of the UBMs 122 is extended and partiallyexposed to form a test pad 124. In this embodiment, as shown in FIG. 2A,it is characterized in that the composite bumps 123 can be made ofAu/Cu. Alternatively, the composite bumps 123 can be made of Au/Ni/Cu,in which Ni is formed between Au and Cu, as a barrier as shown in FIG.2B. It is noted that Au of the composite bump 123 forms a thicknesswhich is less than a half of the total height of the composite bump 123for reducing the costs. As shown in FIG. 2C, another preferredembodiment of the composite bumps 123 further comprises a layer 125 madeAu covering the bump 123. The chips 12 are bonded onto the substratefilm 11 by using the composite bumps to electrically connect to theterminals 111 respectively. For enhancing the conductivity, a coverlayer 113 made of Ni/Au or Sn is formed on the terminal 111.

In order to prevent from humidity leaking into the packaging structure 1and affecting the conductivity, the packaging structure 1 furthercomprises non-conductive pastes (NCPs) 112 being formed between thechips 12 and the terminals 111. Furthermore, as shown in FIG. 1C, thepackaging structure 1 may further comprise a plurality of solder balls16 disposed on a surface of the substrate film 11 opposite to the chips12.

Another embodiment of the present invention regarding to the method formanufacturing the aforesaid packaging structure 1 is disclosedhereinafter. Please refer to FIG. 3 and FIG. 6A simultaneously. The step601 is performed to provide a substrate film 11 being formed withcircuits having a plurality of terminals 111 exposed from the soldermask 15. Preferably, a cover layer 113 is formed onto the terminal 111,wherein the cover layer 113 can be made of Ni/Au or Sn. Then, the step602 is applying a non-conductive paste (NCP) 112 onto the substrate film11 to overlay the terminals 111. The step 603 is providing a pluralityof chips 12, wherein each of the chips 12 has a plurality of pads 121and a plurality of composite bumps 123 disposed onto the pads 121, asshown in FIGS. 1B to 2C. In this embodiment, the chip 12 furthercomprises an under bump metal (UBM) 122 overlaying on the pad 121.Similar to the aforesaid embodiment, each of the composite bumps 123 canbe made of Au/Cu or Au/Ni/Cu, wherein Au forms a thickness which is lessthan a half of a height of the composite bump 123 for reducing thecosts.

In step 604, the plurality of chips 12 is bonded onto the substrate film11, wherein the plurality of composite bumps 123 electrically connect tothe terminals 111 respectively. More specifically, as shown in FIG. 4,the step of bonding the plurality of chips 12 onto the substrate film 11is applying ultrasonic waves to the chips 12 to drive the compositebumps 123 penetrating the NCP 112 to electrically connect with theterminals 111. The NCP 112 is then cured in step 605. Thus, the firsttape 1 a is formed as shown in FIG. 5A.

Subsequently, referring to FIG. 5B, the second tape 1 b having a supportlayer 14 and a compound resin layer 13 being applied on the supportlayer 14 is provided in step 606. In Step 607, the first tape 1 a andthe second tape 1 b are formed into reels 2 a and 2 b to facilitate thefollow-up processes.

Referring to FIG. 6B and FIG. 1, step 608 is performed to expand andtransport the first tape 1 a and the second tape 1 b towards a pair ofrollers 3. The second tape 1 b can be pre-heated to soften the compoundresin layer 13 thereof in step 609 by using a pre-heat device 4. Then,step 610 is performed to heat and pressurize the first tape 1 a and thesecond tape 1 b with each other by the rollers 3 to implant the chips 12within the compound resin layer 13. Preferably, the rollers 3 heat thefirst tape 1 a and the second tape 1 b to the temperature from 100 to250 degrees centigrade. Then, the first tape 1 a and the second tape 1 bcan be cured in step 611 by using a curing device 5. After step 611, instep 612, the support layer 14 can be removed.

Finally, the first tape 1 a and second tape 1 b which are being combinedare cut into a plurality of units 1′ in step 613. Also referring to FIG.1C, in step 614, the solder balls 16 can be mounted onto the substratefilm 11 at the surface opposite to the chips 12 in each of the units 1′.

According to the aforesaid disclosures, the composite bumps used in thepackaging structure can reduce the manufacturing cost due to minimizingthe use of Au. Also, the processes of manufacturing the packagingstructure in the reel-to-reel manner are adopted in mass production.

The above disclosure is related to the detailed technical contents andinventive features thereof. People skilled in this field may proceedwith a variety of modifications and replacements based on thedisclosures and suggestions of the invention as described withoutdeparting from the characteristics thereof. Nevertheless, although suchmodifications and replacements are not fully disclosed in the abovedescriptions, they have substantially been covered in the followingclaims as appended.

1. A method for manufacturing a packaging structure, comprising stepsof: providing a substrate film being formed with circuits having aplurality of terminals exposed from a solder mask; providing a pluralityof chips, each of the chips having a plurality of pads and a pluralityof composite bumps disposed onto the pads; bonding the plurality ofchips onto the substrate film being applying ultrasonic waves to thechips to drive the composite bumps penetrating a non-conductive paste(NCP) to electrically connect with the terminals so as to form a firsttape, wherein the plurality of composite bumps electrically connect tothe terminals respectively; providing a second tape having a supportlayer and a compound resin layer being applied thereon; forming each ofthe first tape and the second tape into a reel; expanding andtransporting the first tape and the second tape towards a pair ofrollers; pre-heating the second tape to soften the compound resin layerthereof; and heating and pressurizing the first tape and the second tapewith each other to a temperature from 100 to 250 degrees centigrade by apair of rollers to implant the chips within the compound resin layer. 2.The method as claimed in claim 1, further comprising a step of applyingthe NCP onto the substrate film to overlay the terminals after the stepof providing a substrate film.
 3. The method as claimed in claim 1,wherein the step of providing a plurality of chips further comprises astep of overlaying an under bump metal (UBM) on the pad.
 4. The methodas claimed in claim 1, wherein the step of providing a substrate filmbeing formed with circuits further comprising a step of: forming a coverlayer onto the terminal, wherein the cover layer is made of Ni/Au or Sn.5. The method as claimed in claim 1, wherein each of the substrate filmand the support layer is made of polyimide (PI) or polyethyleneterephthalate (PET).
 6. The method as claimed in claim 1, wherein thecomposite bumps are made of Au/Cu or Au/Ni/Cu.
 7. The method as claimedin claim 6, wherein Au of the composite bump forms a thickness which isless than a half of a height of the composite bump.
 8. The method asclaimed in claim 1, further comprising a step of curing the NCP afterthe step of applying ultrasonic waves to the chips.
 9. The method asclaimed in claim 8, further comprising a step after the step of heatingand pressurizing the first tape and the second tape: curing the firsttape and the second tape.
 10. The method as claimed in claim 9, furthercomprising a step after the step of curing the first tape and the secondtape: removing the support layer of the packaging structure; cutting thefirst tape and second tape into a plurality of units; and mountingsolder balls onto the substrate film opposite to the chips in each ofthe units.